The following definition is taken from Wikipedia.org Here.
In computing, Desktop Virtualization involves separating the physical location where the PC desktop resides from where the user is accessing the PC. A remotely accessed PC is typically either located at home, at the office, or in a data center. The user is located elsewhere, perhaps traveling, in [...]

Utility Computing, is also known as on-demand computing, or cloud computing. A Great Definition from wikipedia.org is as follows.
Utility Computing (also known as on-demand computing) is the packaging of computing resources, such as computation and storage, as a metered service similar to a physical public utility (such as electricity, water, natural gas, or telephone network). [...]